libcdecl: Remove "too many parentheses" error check.

[cdecl99.git] / src / parse-decl.c

diff --git a/src/parse-decl.c b/src/parse-decl.c
index 3137859708b5745d24ec489309efd97a0edfdd69..c3ba32db8b3ed177dccf4873b98f61d16d4494da 100644 (file)
--- a/src/parse-decl.c
+++ b/src/parse-decl.c
@@ -234,26 +234,33 @@ simplify_functions(struct cdecl_declarator **p, struct cdecl_declarator *d)
 }
 
 /*
- * The parser's bias towards considering things as functions whenever possible
- * makes nested parentheses tricky.  (x) is considered to be part of a function
- * declarator until simplify_functions converts it.  The problem is that
- * (((x))) is not valid as part of a function declarator, but it *is* valid
- * as an identifier enclosed 3 times in parentheses.  This is complicated by
- * the fact that things like (((int))) are not valid anywhere.
+ * The main parser's bias towards considering things as functions whenever
+ * possible makes nested parentheses tricky.  "(x)" is considered to be part
+ * of a function declarator until simplify_functions converts it.  The problem
+ * is that "(((x)))" is not valid as part of a function declarator, but it _is_
+ * valid as either an identifier enclosed thrice in parentheses, or an abstract
+ * function declarator enclosed twice in parentheses.
  *
- * To avoid ambiguities, the parser actually emits a "function" declarator for
- * every pair of parentheses.  The ones that can't reasonably be functions
- * consist of a single "parameter" with no declaration specifiers (note that
- * every valid function parameter will have at least one type specifier).
+ * To avoid ambiguities, the main parser actually returns a function declarator
+ * for every pair of parentheses.  The ones we need to look at consist of a
+ * single parameter with an empty specifier list (noting that every real
+ * function parameter will have at least one type specifier).
  *
- * This pass is to remove these fake functions from the parse tree.  We take
- * care to avoid turning invalid things like ((int)) into valid things like
- * (int) by observing that the only valid function declarators that appear
- * in these "fake" parentheses are those that have a non-null child declarator
- * (for instance, int ((*)(int)) *or* those that will be eliminated by the
- * simplify_functions pass.
+ * There are two cases:
+ *
+ *   - For (), the parser emits a parameter with a lone null declarator.
+ *     This fake parameter simply gets deleted, leaving us with a normal
+ *     function declarator with an empty identifier list.
+ *
+ *   - Otherwise, the parameter's outermost declarator is not null.  The
+ *     function itself is deleted, replaced in the parse tree with the
+ *     fake parameter's declarator.
+ *
+ * Repeating until there no fake parameters, this reduction transforms, for
+ * example, "(((x)))" into "(x)", an abstract function declarator.  The result
+ * is then subject to the function simplification step, which will turn "(x)"
+ * into x (declaring an identifier).
  */
-
 static struct cdecl *fake_function_param(struct cdecl_declarator *d)
 {
        struct cdecl *param;
@@ -273,7 +280,6 @@ static int
 reduce_parentheses(struct cdecl_declarator **p, struct cdecl_declarator *d)
 {
        struct cdecl *param;
-       int fake = 0;
 
        while ((param = fake_function_param(d))) {
                struct cdecl_declarator *decl = param->declarators;
@@ -289,19 +295,12 @@ reduce_parentheses(struct cdecl_declarator **p, struct cdecl_declarator *d)
 
                        param->declarators = d;
                        *p = d = decl;
-                       fake = 1;
                }
 
                cdecl__free(param);
        }
 
        simplify_functions(p, d);
-       if (fake && (*p)->type == CDECL_DECL_FUNCTION) {
-               /* Started with a fake function but ended with a real one. */
-               cdecl__errmsg(CDECL__EMANYPAREN);
-               return -1;
-       }
-
        return 0;
 }